The present invention generally relates to apparatus and methods for a contoured turbine rotor hub. More specifically, the present invention relates to apparatus and methods relating to a turbine rotor hub comprising a cambered surface.
Turbine engines may include a compressor section, wherein inlet air is compressed, followed by a combustor section wherein fuel is combusted with the compressed air to generate exhaust gas. The exhaust gas is then directed to a turbine section, wherein energy is extracted from the exhaust gas. Turbine engines including the compressor and turbine sections may comprise a series of confined passages wherein a cascade of stationary vanes and rotating blades are arranged to produce and then remove energy from a working fluid (i.e., from combustion of a fuel.) The geometry and positioning of these vanes and blades relative to one another may determine the efficiency at which a particular turbine engine operates.
U.S. Pat. No. 2,735,612 is directed to improvements in passage configurations for interblade passages in compressor sections and diffusers such as in an air inlet diffuser of a gas turbine engine; the reference does not disclose configurations of the turbine section hub.
U.S. Pat. No. 6,561,761 is directed to a compressor section flow path which includes circumferentially spaced apart airfoils having axially spaced apart outer and inner ends. An outer wall bridges the airfoil outer ends, and an inner wall bridges the inner ends. One of the walls includes a flute adjacent the leading edge for locally increasing flow area thereat. Again, the '761 patent does not disclose modifications of the turbine section hub.
In addition to compressor flow paths, gas turbine engines may also include turbine section flow paths to and from turbine rotors having rotating blades positioned within the exhaust stream to extract energy from exhaust gasses produced during the combustion process. The flow paths to and from turbine rotors may also comprise stationary vanes and other surfaces which may be dimensioned and arranged within the exhaust gas flow path to optimize the amount of energy extracted, and extend rotor life.
While prior references are directed to turbine rotor blade design, the space between the turbine rotor blades, referred to herein as the turbine rotor hub region, and the turbine rotor flow path between the airfoils generally has been largely ignored. Prior art turbine rotor flow paths are typically comprised of a straight flat surface from the rotor leading edge to the rotor trailing edge along the rotor hub.
As can be seen, there is a need for optimization of flow paths relating to the turbine rotor hub of a gas turbine engine.